Lungs infected with plague bacteria also become playgrounds for other microbes

Among medical mysteries baffling many infectious disease experts is exactly how the deadly pneumonic plague bacterium, Yersinia pestis, goes undetected in the first few day of lung infection, often until it's too late for medical treatment.

New research from the University of North Carolina at Chapel Hill School of Medicine has opened a door to the answer. Researchers led by William E. Goldman, PhD, professor and chair of microbiology and immunology at the University of North Carolina at Chapel Hilland a leading authority on Y. pestis, show that the plague bacteria transform the lungs from a nasty place for microbes into a playground for them to flourish.

Goldman notes that most other microbes that infect the lungs trigger an antimicrobial response within a few hours after infection. This early inflammatory response is generally sufficient to eliminate microorganisms with no more than mild respiratory symptoms. Not so with Y. pestis; for about 36 hours, the lungs are "quiet," not inflamed, and symptoms are completely absent.